The invention relates to a two-axis rate gyro with elastic articulation elements.
An angular velocity sensor for navigation purposes with a rotating gyro element is known from German Patent Document DE 36 19 941 A1, said element being secured mechanically by means of a piezoelectric crystal acting leverwise. When an angular velocity occurs around an axis perpendicular to the operating axis of the device, the piezoelectric crystal is bent leverwise, delivering an electrical signal. In this gyro, the piezoelectric crystal is long relative to its restraint so that relatively large measuring deflections occur under stress caused by angular velocity. Thus, the gyro does not have very rigid restraint, shows considerable nonlinearity of the measurement deflection, and has a relatively large coupling error that depends on the measuring deflection.
An object of the invention is to provide elastic articulation elements for a two-axis rate gyro that ensure a very rigid restraint of the gyro and hence minimal linear measuring deflections.
This object is achieved according to preferred embodiments of the invention by providing a two-axis rate gyro comprising: a drive shaft, a gyro rotor, first and second articulation elements arranged axially and sequentially, the first articulation element being connected with the drive shaft and the second articulation element being connected with the gyro rotor, the two articulation elements being connected together by two narrow ribs located laterally with respect to a central bore and perpendicularly with respect to a central axis of the articulation elements, and spring elements acting on pretensioned force-measuring elements and being tensioned with respect to one another, the spring elements deforming elastically and symmetrically around the ribs under the influence of a sinusoidally alternating torque during operation of the gyro with the force-measuring elements being loaded and unloaded alternately and generating measurement signals proportional to the forces acting on them.
An important advantage of the articulation elements with quasi-rigid spring elements according to the invention consists in the resultant rigid restraint of the gyro. Consequently, only very small measuring deflections occur, with minimal deviation from linearity and negligible coupling errors over the entire measurement range. All of these properties produce high dynamics for the gyro, i.e. the ratio of the measurement range to the resolution or response sensitivity. A dynamic of 1/10,000 or more is reached, corresponding for example to a measurement range from 1,000.degree./sec to 0.01.degree./sec resolution. In particular, preferred embodiments with the spring elements designed as expansion bolts have the advantage of a simple, compact design utilizing conventional commercial spring and force elements.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.